code: def test_multi_process(idtype):
      hg = create_test_graph(idtype=idtype)
      hg_share = hg.shared_memory("hg1")
      p = mp.Process(target=sub_proc, args=(hg, "hg1"))
      p.start()
      p.join()
  
file_path: dgl/tests/python/common/test_heterograph-shared-memory.py
imports: import io
  import multiprocessing
  import os
  import pickle
  import unittest
  import backend
  import dgl
  import dgl.function
  import networkx
  import scipy.sparse
  from dgl.graph_index import create_graph_index
  from dgl.utils import toindex
  from utils import parametrize_idtype
label_desc: Use image node_id 5 for calling a global function with example usage: test_multi_process(idtype) without return types